Lubricant compositions



United States Patent LUBRICANT CGMPOSITIONS Norman E. Lemmon, Whiting, Ind., and Ellis K. Fields,

Chicago, Ill., assignors to Standard Oil Company, Chicage, 11]., a corporation of Indiana N 0 Drawing. Application September 29, 1955 Serial No. 537,588

Claims. (Cl. 25232.7)

This invention pertains to improved lubricant'compositions and in particular to internal combustion engine lubricant compositions which inhibit corrosion, rusting and the pitting and/or wear of the operating parts of the engine.

Many modern automobile engines are designed with hydraulic valve-lifters for smoother and more efficient engine operation. In the operation of hydraulic valvelifters, the lifters ride on the cam shaft converting the rotary motion of the cam into a reciprocating motion, which in turn opens and .closes the valves. The bottom of the valve-lifter is known as the cam follower. The hydraulic part of the valve-lifter functions by means of a plunger on the inside of the valve lifter barrel, together with a ball-check and a spring. To obtain higher efficiency and greater horsepower, larger valves, high valve spring pressures and camshafts which produce more rapid valve opening and closing are employed. In the operation of such engines, greatly increased pressures are encountered where the camshaft lobes come into contact with the faces of the valve-lifters resulting in excessive and severe cam and lifter wear as well as pitting of the cam followers. This wear and/ or pitting cannot be adequately inhibited by most present-day internal combustion engine crank-case lubricants. Surprisingly, the type of anti-wear properties which will inhibit piston'ring and/ or cylinder wear are not necessarily the same as the antiwear properties necessary to prevent cam and lifter wear and/ or pitting; hence many lubricants which are elfective in inhibiting ring and cylinder wear are ineffective in preventing cam and lifter wear. A further complicating factor in this problem is caused by the materials used in making the camshaft and valve-lifters since different metals and metal combinations are used for this purpose in the various engines. Furthermore, because of the small clearances between the plunger and the barrel of hydraulic valve-lifters, extremely small amounts of deposits such as varnish and/ or rusting may cause sticking of the valve-lifter. Hence, it is essential for good engine operation to provide a lubricant which will, in addition.

to inhibit wear and/ or pitting, also inhibit the formation of varnish and/ or rusting in the valve-lifter. I

It is an object of this invention to provide a lubricant composition which will be substantially free of any tendency to cause valve lifter sticking and/or rusting and which will have improved cam follower anti-pitting and anti-wear properties. lubricant for internal combustion engines which is improved with respect to oxidation stability, detergency, and dispersant powers. A further object of the invention is to provide a method of reducing or eliminating the sticking of hydraulic valve-lifters, the pitting and/or wear of cam followers, and the corrosion of bearings in internal combustion engines. Other objects and advantages will become apparent from the following description thereof.

In accordance with the herein described invention, the

above objects can be attained by incorporating in a viscous Another object is to provide a oil, i. e, an oil having a Saybolt Universal viscosity above about 80 seconds at 100 F., containing between about 0.002 and 10% of a neutralized phosphomsand sulfurcontaining detergent-type lubricating oil additive, between about 0.001 and 5% of an amine salt of the polymerization products of unsaturated fatty acids. The detergenttype additive may be one such as an alkaline earth metal, e. g. barium, neutralized reaction product of a phosphorus sulfide and a hydrocarbon such as butylene polymers, including those additives which have excess basicity. The amine employed in forming the salts of the polymerized fatty acids is an oil-soluble aliphatic monoamine such as octadecyl amine. The polymerization products of the unsaturated fatty acids, e. g. linoleic acid, have a molecular weight between about 400 and 2000. a

While the polymerization pro-ducts of unsaturated fatty acids improve the anti-wear, anti-pitting, and anti-rusting properties of the lubricant containing the detergent additive, the improvement is often insufficient and the oxidation stability of the oil is reduced. This causes an increase in the erosion in the bearing surfaces ..of the internal combustion engine. It has been found that these deficiencies in the use of the polymerization products of the unsaturated fatty acids can be eliminated by employing the aliphatic mono-amine salts thereof.

It has also been found thatthe pitting and/or wear, as well as the rusting problem, occurring in hydraulic valve lifters is markedly increased when using a neutral-l i zed phosphorous-and sulfur-containing detergent-type-additive which has an excess basicity. These highly basic detergent additives i. e. those which contain a metal constituent in excess of that stoichiometrically necessary to neutralize the acidic hydrogen atoms, are being'used to an increasing extent since they furnish an alkaline're-.

serve which neutralizes acid compounds formed in the oxidation of gasoline or oil and also provide improved detergent and dispersant power. It appears that the prob-l lem of pitting, wear, and/ or rusting increases as the amount of excess basicity of the detergent additive increases. It has been discovered that the amine salts of the polymerization products of the unsaturated fattyacids are effective in greatly reducing or eliminating completely this aggravated problem. The presence of between about 0.001 and 5% of an oil soluble aliphatic mono-amine in the lubricating oil composition which contains the detergent additive and the amine salt of the polymerization products of the unsaturated fatty acids, improves the antirust properties of the lubricating oil composition further. I

The detergent-type lubricating oil additive used is one which contains phosphorus and sulfur. The function of this type of additive is to inhibit the formation of sludge and/or varnish-like products which are deposited in the engine and/or about the valves and rings of the engine. Detergent additives of this type are usually used in amounts of from about 0.002 to about 10%, and preferably from about 0.01% to about 5%. Among the phosphorusand sulfur-containing addition agents are. the neutralized reaction products of a phosphorus sulfide and a hydrocarbon, an alcohol, a ketone, an amine or an ester. Of the phosphorus sulfide reaction product a'dditives, the neutralized reaction products of a phosphorus sulfide, such as a phosphorus penta-sulfide, and a hydrocarbon (note U. S. 2,3l6,082) are preferred.

The preferred hydrocarbon used for reactionwith the phosphorus sulfide is a mono-olefin hydrocarbon polymer resulting from the polymerization of low molecular weight mono-olefin hydrocarbons, such as propylene, butylenes, amylenes or copolymers thereof. Such polymers maybe obtained by the polymerization of mono-olefins of less than 6 carbon atoms in the presence of a catalyst, such even as sulfuric acid, phosphoric acid, boron fluoride, aluminum chloride or' other similar halide catalysts of the Friedel-Crafts type.

The polymers employed are preferably mono-olefin polymers or mixtures of mono-olefin polymers and isomono-olefin polymers having molecular weights ranging from about 150 to about 50,000 or more, and preferably from about 500 to about 10,000. Such polymers can be obtained, for example, by the polymerization in the liquid phase of a hydrocarbon mixture containing monoand isomono-olefins, such as butylene and isobutylene at a temperature of from about 80 F. to about 100 F. in the presence of a metal halide catalyst of the Friedel- Crafts type, such as for example, boron fluoride, aluminum chloride, and the like. In the preparation of these polymers, a hydrocarbon mixture containing isobutylene, butylenes and butanes recovered from petroleum gases, especially those gases produced in the cracking of petroleum oils in the manufacture of gasoline can be used.

Parafinic hydrocarbons such as bright stock residuums, lubricating oil distillates, waxes, and the like can be reacted with phosphorus sulfide. Olefins having 16 to 30 carbon atoms or higher may be reacted with the phosphorus sulfide. Other hydrocarbons that can be reacted with a phosphorus sulfide are aromatic hydrocarbons such as benzene, naphthalene, diphenyl, alkylated aromatic hydrocarbons such as benzene having alkyl substituents containing preferably at least 8 carbon atoms, and the like.

The phosphorus sulfide-hydrocarbon reaction product can be readily obtained by reacting a phosphorus sulfide, for example P 8 with the hydrocarbon at a temperature of from about 200 F. to about 500 F., and preferably from about 200 F. to about 400 F., using from about 1% to about 50%, and preferably from about 5% to about 25% of the phosphorus sulfide in the reaction. It is advantageous to maintain a non-oxidizing atmosphere, such as for example, an atmosphere of nitrogen above the reaction mixture. Usually, it is preferable to use an amount of the phosphorus sulfide that will completely react with the hydrocarbon so that no further purification becomes. necessary; however, an excess amount of phosphorus sulfide can be used and separated from the product by filtration or by dilution with a hydrocarbon solvent, such as hexane, filtering and subsequently removing the solvent by suitable means, such as by distillation. If desired, the reaction product can be further treated with steam at an elevated temperature of from about 100 F. to about 600 F.

The phosphorus sulfide-hydrocarbon reaction product normally shows a titratable acidity which is neutralized by treatment with a basic reagent. The term neutralized reaction product of a phosphorus sulfide and a hydrocarbon as used herein means a phosphorus sulfide-hydrocarbon reaction product having at least 1% of its titratable acidity neutralized by the reaction with a basic reagent. The phosphorus sulfide-hydrocarbon reaction product when neutralized with a basic reagent containing a metal constituent is characterized by the presence or retention of the metal constituent of the basic reagent.

The term neutralized reaction product of a phosphorus sulfide and hydrocarbon also includes those products which contain the metal constituent in excess of the amount stoichiometrically necessary to replace the acidic hydrogens contained in the phosphorus sulfidehydrocarbon reaction product. Such compounds which have this excess amount of metal constituent are known in the art as having excess basicity. They have also been called highly basic, as well as, compounds which have an alkaline reserve which serves to neutralize the acids which are formed in the oxidation of the gasoline and/or sulfur compounds contained therein and/ or lubricating oil. The highly basic detergents also have improved detergent and dispersant properties. All of such terms have been used to describe those neutralization products which contain an amount of metal in excess of that required to form the normal neutralization products of the acidic phosphorus sulfide-hydrocarbon reaction product.

In general those detergent additives which have excess basicity may contain between 0.5 and 5 moles of the metal constituent per mole of phosphorus contained in the phosphorus sulfide-hydrocarbon reaction product; the particular amount varies with the acidity of the reaction product of phosphorus sulfide and a hydrocarbon, the valence of the metal constituent, and the degree of basicity desired. For example when the metal constituent is barium, the normal neutralization products may contain up to about 3 parts of barium per part of phosphorus by weight in the neutralized phosphorus sulfide-hydrocarbon reaction product. If a product having excess basicity is desired then a weight ratio of between about 4 and 15 parts e. g. 5 parts of barium per part of phosphorus in the phosphorus sulfide-hydrocarbon reaction product should be used. excess basicity may conveniently be made by neutralizing the acidic phosphorus sulfide-hydrocarbon reaction product with an amount of basic reagent inexcess of that necessary to replace the acidic hydrogen atoms contained therein. Prior to neutralization the reaction product can be hydrolyzed and clayed to remove inorganic acids of phosphorusas described in U. S. 2,688,612 issued to R. W. Watson September 7, 1954.

The neutralized phosphorus sulfide-hydrogen reaction product can be obtained by treating the acidic reaction product with a suitable basic compound, such as hydroxide, carbonate, oxide, or sulfide of an alkali or alkaline earth. metal, such as for example, potassium hydroxide, sodium hydroxide, sodium sulfide, and calcium oxide,'lime, barium hydroxide, barium oxide, etc. The neutralization of the phosphorus sulfide-hydrocarbon reaction product is carried out preferably in a non-oxidizing atmosphere by contacting the acidic reaction product either as such or dissolved in a suitable solvent, such as naphtha with a solution of the basic agent. As an alternative method the reaction product can be treated with solid alkaline compounds such as KOH, NaOI-I, Na CO CaO, BaO, Ba(OH) Na S, and the like, at an elevated temperature of from about F. to about 600 F. Neutralized reaction products containing a heavy metal constituent, such as for example, tin, titanium, aluminum, chromium, cobalt, zinc, iron, and the like, can be obtained by reacting a salt of the desired heavy metal with the phosphorus sulfide-hydrocarbon reaction product which has been treated with a basic reagent such as abovedescribed.

The amine uscd in forming the amine salt of the polymerization products of unsaturated fatty acids are aliphatic mono-amines. The amines are of the oil-soluble type. They may have between 8 and 24 carbon atoms. Particularly suitable aliphatic amines are the primary mono-amines such as for example, octadecyl amine. The aliphatic hydrocarbon radical may have either a straight'or branched chain. Aliphatic polyamine salts of the polymerization products of the unsaturated fatty acids are not sufficiently soluble in the oil.

In forming the amine salt with a single amine or a mixture of amines, the amines used may be chemically pure products or of a commercial quality. Suitable primary aliphatic mono-amines may be obtained by converting the fatty acids, derived from natural fatty acid glycerides, and the nitrilcs and then reducing the nitriles, for example at temperatures below C. and under alkaline conditions, principally to the primary amines. Depending upon the fatty acid used, the aliphatic amines usually contain from about 8 to about 18 carbon atoms. Suitable amines are the products manufactured according to this general procedure and sold under the trade name Armeen, such as Armeen 8, Armeen 10D, Armeen 14, Airncen 16, Armeen 18 (the Armeens contain a mixture of amines, the principal constituent of. which has the number of These additives which have carbon atoms indicated after the trade name Armeen). Other aliphatic mono-amines which may be employed are the Primenes. These are mixtures of substantially primary amines having molecular weights of from about 185 to 350, and whose alkyl chains are branched.

The polymerization products of the unsaturated fatty acids, from which are formed the amine salts, are those such as may be obtained by the polymerization of natural or synthetic mono-carboxylic acids which generally will have 16 to 26 carbon atoms, most frequently 18 carbon atoms, but if synthetic unsaturated fatty acids are used they may have a lesser or greater number of carbon atoms. Examples of the natural fatty acids are those such as linoleic, linolenic, ricinoleic (which upon heating forms linoleic acid), linoleaidic, elaidolinolenic, 'eleostearic, arachidonic, eicosatrienoic, cetoleic, docosatrienoic and the like. The free fatty acids can be polymerized either thermally or with the assistance of catalysts. A method of thermally polymerizing free fatty acids (see U. S. 2,482,761) consists of hydrolyzing a fat or an oil, adding a small portion of water, andheating in a pressure vessel until substantially all of the diand tri-unsaturated fatty acids present polymerize. The resultant product is then heated at a reduced pressure to distill olf vaporizable constituents, leaving behind the polymerized unsaturated fatty acids. The polymerization reaction is carried out at a temperature of about 300 to 360 C. for about 3 to 8 hours at a pressure vary- 'ing between 75 and 500 p. s. i. g. The polymerization product may consist of monomers, dimers, trimers, and higher polymers of the unsaturated fatty acids. The various fats or oils which may be hydrolyzed to produce the free fatty acids used in the above thermal polymerization are those such as sardine oil, linseed oil, soybean oil, castor oil, peanut oil, palm oil, olive oil, cottonseed oil, sunflower seed oil, and the like.

Another method of preparing the polymerized fatty acids consists of subjecting fats and oils such as have been listed supra (without previous hydrolysis) to a thermal or catalytic polymerization to cause polymerization of the esters of the unsaturated carboxylic acids to the dimers, trimers, and higher polymerization products thereof, followed by hydrolysis to yield the corresponding polymers of the acids. A large source of the polymerized unsaturated fatty acids are those residual acids obtained by methanolysis (see U. S. 2,450,940) of the semi-drying or drying type oils such as castor oil, soybean oil, and others listed supra, polymerizing the methyl esters, removing unpolymerized compounds, saponifying the residual esters and freeing polymerized acids therefrom. The products of catalytic polymerization of semi-drying oils such as the BF polymerization products of soybean oil, cottonseed oil, or the like also produce polymers suitable for use in the invention.

It should be understood that while various polymerized unsaturated fatty acids maybe used, they do not all provide the same effect, and indeed there may be pronounced differences when used in the composition of this invention. A highly preferred source of the polymerized unsaturated fatty acids is obtained as a byproduct still residue in the manufacture of sebacic acid by the dry distillation of castor oil in the presence of sodium hydroxide. A method of obtaining such byproduct still residues in the manufacture of sebacic acid is described in U. S. 2,470,849 issued to W. E. Hanson May 24, 1949. The mixture of high molecular weight unsaturated fatty acids comprises monomers, dimers, trimers and higher polymers in the ratio of from about 45% to about 55% of a monomers and dimers fraction having a molecular weight in the range of from about 300 to 600, and from about 45% to about 55% of a trimers and higher polymer fraction having a molecular weight in excess of 600. The fatty acid polymers result in part from a thermal polymerization of fatty acid type 6 constituents of the castor oil, and in part from other reactions, such asthe inter-molecular esterification, of such acid to form high molecular weight products. The acid mixture, which is mainly amixture of polymeric long chain polybasic carboxylic acids, is further characterized by the following specifications:

Acid N0. 150 to 164 Saponification No. 175 to 186 Free fatty acids percent 75 to 82 Iodine value 44 to Non-saponifiables percent 2.5 to 5 A fatty acid mixture such as above described is marketed under the trade name D-50 Acids, and also as VR-l Acids.

The polymerization products of the unsaturated fatty acids may have a molecular weight between about 400 and 2000. Those polymers having a molecular weight higher than about 500, and especially those having molecular weights averaging about 800 or higher are particularly preferred for use in this invention. The polymerization products may consist primarily of dimers and trimers of linoleic acid, for example Emery 955 dimer acid which contains 85% of the dimer, 12% of the trimer, and 3% of the monomer of linoleic acid may be used. Especially preferred polymerized unsaturated acids are the polymerization products of acids such as linoleic acid having a molecular weight between about 400 and 2000, wherein the polymerization products consist of more than about 40% of the trimer and higher molecular weight polymers of linoleic acid with the remainder consisting primarily of monomers and dimers of linoleic acid.

The amine salts may be prepared by reacting, under carefully controlled, non-dehydrating conditions, i. e. below about 200 F., the amine and the polymerization products of the unsaturated fatty acids. Care must be taken in the preparation of such salts inasmuch as prolonged exposure to temperatures higher than about 200 F. results in the formation of amides upon separating out water. The amine salts may be preformed by effecting the reaction in a volatile solvent which is then distilled from the amine salt, or it may be prepared in a hydrocarbon oil. The amine salts may be formed in situ in the lubricating oil composition by adding thereto the reactants i. e. the amine and the polymerization products of the unsaturated fatty acids. While the use of one mole of the amine per carboxylic acid group contained in the polymerization products of the unsaturated fatty acids is necessary to form the amine salts, if a larger amount of the amine is employed it exists in the free state. Upon the addition of a mixture of the amine salt together with free amine to the lubricating oil improved anti-rust properties are obtained.

The phosphorusand sulfur-containing detergent-type additive and the amine salt of the polymerization products of unsaturated fatty acids can be added individually to the lubricating oil base or they can be pre-mixed (preferably together with the detergent-type additive) in the desired proportions and the resultant mixture then added to the lubricating oil base. Concentrations of a suitable oil base containing more than 10%, for example up to 50% or more, of the detergent-type additive, alone or in combination with more than about 5%, for example up to 25% or more, of the amine salt, can be used for blending with the hydrocarbon oils in the proportions desired for the particular conditions of use to provide a finished valve-lifters .weremade. The tests made to determine" the anti-pitting and anti-wear properties of the oil is known as the L-S-S test. established by the General Motors Re search Division. The test is made on a 1953 Chevrolet power glide engine equipped with chilled iron lifters, forged steel cams, steel rocker arm shafts, malleable iron rocker arms and operating at 3150 R. P. M. with a load of 30 brake horsepower, an oil sump temperature of 255 F and a water outlet temperature of 200 F. Dual valve springs are installed to give an assembled static valve spring load of 240 pounds at.0.330 inchvalve opening. The test is continued for 24 hours at the end of which the cam followers are inspected for pitting and over-all wear.

The effectiveness of the additives for preventing pitting of the cam followers is shown in the table which follows. In obtaining the data presented in this table various additives for preventing pitting and/or wear of the cam followers were added either to OilComposition A of Oil Composition B and the mixtures then evaluated. Oil

Compositions A and B were composed of the following:

Oil Composition A-SAE W-20 oil plus 3.0% of a barium-containing neutralized reaction product of P 8 and a polybutene of about 1000 molecular weight (having a barium to phosphorus weight ratio of approximately 3:1, that is to say having no excess alkalinity or basicity) plus 0.67% of a sulfurized dipentene (35% sulfur) plus 4.6% of a V. I. improver plus p. p. m. anti-foam agent.

Oil Composition B-SAE 5W-20 oil plus 5.5% of a barium-containing neutralized reaction product of P 5 and a polybutene of about l000'molecular. weight (having a barium to phosphorus weight ratio ofabout 5:1, i. e. having excess basicity) plus 0.75%, of a. sulfurized dipentene sulfur) plus 10 p. p. m. antifoam agent. The results show:

L-S5 engine tests 1 Estimated. Samples 1 and 4 show that unless an anti-pitting and'antiwear additive is present in the oil almost all of the cam follower surfaces will be pitted. Sample 4 shows that when the detergent additive has excess basicity, the degree of pitting and/ or wear is increased. Samples 2 and 5 sh'ow that the pitting and/or wear problem is not eliminated merely by using the polymerization products of theun saturated fatty acids (the compositions of the commercial polymerized fatty acids used here have been detailed previously). Sample 3 shows that when the amine salt, prepared from Emery 955 Acid and Primene JMR octadecylamine, is used in the oil, only two lifters are pitted; Sample 6 shows that when the amine salt, prepared from D Acid and Armeen T which consists of the technical mixture of amines prepared from tallow, is used in the oil, it enables the oil to pass the L-S-S test and allows only 1 cam follower to-become pitted. This is accom- 1 plished when using only one-third as much of the antipitting additive as was employed in Sample 5.

An additional series of samples were evaluated to determine the ability of various additives to prevent rusting of the hydraulic valve-lifters. The test employed is called the modified Indiana hydraulic valve lifter rust test. This test is carried out in a Chevrolet power-glide engine opcrating at 2500, R. P. M. and a load of 45 B. H. P. with an. oil temperature of F. and a water temperature of 85-95" F. The test engine is operated at these conditions for 20 hours with a 4 hour running and 4 hour off cycle. At the end of 20 hours the dipstick, rocker arm shaft and valve lifters are inspected for rust. Valve lifters free of. rust are rated 10 and. badly rusted lifters are rated 1.

The oil samples employed in this test were portions of Oil Composition B which was previously described. The effectiveness of different additives for preventing rusting and/ or corrosion in the hydraulic valve-lifters rust shown in the table which follows:

Modified Indiana hydraulic valve lifter rust test Sample 4 shows that it is imperative to employ an additivefor inhibiting the rusting of the valve lifters. Sample 7 indicates that the D-50 Acid reduces the amount of rusting. Best results, however, can be obtained when employing the amine salt (Armeen T was employed) of the polymerized unsaturated fatty acids.

The advantage of employing free amine in the lubrieating oil composition containing the detergent and amine salt of the polymerized unsaturated fatty acids was demonstrated in accelerated rusting tests in Water. The tests demonstrated that the presence of free amine in the oil containing the detergent additive and the amine salt of the polymerization products of the unsaturated fatty acids provided rust protection for twice the length of time as was provided when no free amine was present.

Additional tests evaluating lubricating oils containing different anti-pitting and anti-wear compounds were conducted. L-4 tests which measure the oil stability and insure that the additive does not lower the stability of the oil were made. The L-4 test measures the bearing weight loss. In these tests it was demonstrated that the lubricatingoil containing neutralized phosphorus and sulfurcontaining' detergent additive produces better results in the L-4 test when an octadecyl amine salt of the D-50 Acid was used in place of the 13-50 Acid alone.

While thepresent invention has been described by the use of our additives in petroleum lubricating oils, other lubricating oil bases can be employed. For example oils obtained by thepolymerization of olefins, synthetic lubrieating oils of'the alkylene oxide type, for example, Ucon Oils, and the polycarboxylic acid ester type oils such as the oil-soluble esters of adipic acid, sebacic acid, azelaic acid, etc. may be used.

Unless otherwise stated, the percentages stated herein and in the claims are weight percentages.

Although the present invention has been described with reference to specific preferred embodiments thereof, the invention is not to be considered as limited thereto but includes within its scope such modifications and variations as come within the spirit of the appended claims.

Weclaim:

l. A lubricating oil. composition having improved valve lifter anti-pitting and anti-wear properties compris ing a major proportion of a lubricating mineral oil base, between about 0.002 and 10% of a phosphorus sulfide-hydrocarbon reaction product which has been neutralized with a basic reagent, and between about 0.001 and 5% of an amine salt of the polymerization products of those unsaturated fatty acids which have between 16 and 26 carbon atoms per molecule, said amine being an oil soluble aliphatic mono-amine, and said polymerization products having a molecular weight between about 400 and 2000. v

2. The composition of claim 1 wherein the basic reagent is an alkaline earth metal compound.

3. The composition of claim 1 wherein the phosphorus sulfide-hydrocarbon reaction product has been neutralized with a basic barium compound to produce a product having excess basicity.

4. The composition of claim 1 in which the unsaturated fatty acid is linoleic acid,

5. The composition of claim 1 wherein the polymerization products of the unsaturated fatty acids consist of more than about 40% of the trimer and higher molecular weight polymers, the remainder being essentially monomers and dimers of the unsaturated fatty acids.

6. The composition of claim 1 wherein the amine is a primary octadecyl amine.

7. The composition of claim 1 which also contains between 0.001 and 5% of an oil-soluble aliphatic monoamine.

8. A lubricating oil composition having improved valve lifter anti-pitting and anti-wear properties comprising a major proportion of a lubricating mineral oil base, between about 0.002 and of a barium-containing neutralized reaction product of a phosphorus sulfide and a butylene polymer, said neutralized reaction product having excess basicity, between about 0.05 and 2% of an amine salt of the polymerization products of linoleic acid, said amine being an oil-soluble aliphatic primary mono- 10. An addition agent for formulating a lubricatingv oil composition which has improved valve lifters antipitting and anti-wear properties, said agent comprising a concentrated solution of a mineral oil containing more than 10% of a phosphorus sulfide-hydrocarbon reaction product which has been neutralized with a basic reagent and more than about 5% of an amine salt of the polymerization products of those unsaturated fatty acids which I have from 16 to 26 carbon atoms per molecule, said amine being an oil-soluble aliphatic mono-amine and said polymerization products having a molecular weight between about 400 and 2000, said concentrated solution being capable of dilution with a lubricating mineral oil base to form a homogeneous mixture containing between about 0.002 and 10% of the neutralized phosphorus sulfide-hydrocarbon reaction product and between about 0.001 and 5% of the amine salt.

References Cited in the file of this patent UNITED STATES PATENTS Kelso Apr. 6, 1943 Langer Ian. 6, 1953 

1. A LUBRICATING OIL COMPOSITION HAVING IMPROVED VALVE LIFTER ANTI-PITTING AND ANTI-WEAR PROPERTIES COMPRISING A MAJOR PROPORTION OF A LUBRICATING MINERAL OIL BASE, BETWEEN ABOUT 0.002 AND 10% OF A PHOSPHORUS SULFIDE-HYDROCARBON REACTION PRODUCT WHICH HAS BEEN NEUTRALIZED WITH A BASIC REAGENT, AND BETWEEN ABOUT 0.001 AND 5% OF AN AMINE SALT OF THE POLYMERIZATION PRODUCTS OF THOSE UNSATURATED FATTY ACIDS WHICH HAVE BETWEEN 16 AND 26 CARBON ATOMS PER MOLECULE, SAID AMINE BEING AN OIL SOLUBLE ALIPHATIC MONO-AMINE, AND SAID POLYMERIZATION PRODUCTS HAVING A MOLECULAR WEIGHT BETWEEN ABOUT 400 AND
 2000. 